Thomas evans



(No Model.)

T.EVAN S.

COMPOUND GRATE BAR.

o.- 361,215. Patented Apr. 12, 1887.

' JNVINZ'UEI UNIT D STATES PATENT I OFFICE.

THOMAS EVANS, on rnovmnncn, RHODE ISLAND.

COMPOUND GRATE-BAR.

SPECIFICATION forming part 0: Letters Patent No. 361,215, dated April 12, 1887.

Application filed December 8, 1886. Serial No. 220,981. (No model.)

To aZZ whom it may concern.-

Be it known that I, THOMAS Evans, of Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Compound Grate-Bars, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification.

This invention relates to a compound gratebar for constructing a grate or floor of a firebox of a furnace or the like.

The intense heating and subsequent cooling of grates causes the straight bars of which the grate is ordinarily composed to expand and contract, and consequently distort and rupture the bars themselves and the bar-frame in which the bars are secured.

The object of my invention is to provide a grate-bar that will compensate for the expansion and contraction, and thereby prevent the warping and breaking of the grate.

To the above purpose my invention consists of a compound grate-bar comprising a bar-frame, with which are cast the cross-bars, consisting each of a bar curved in the main and central portion and formed with straight ends, all as hereinafter fully described and claimed.

In the accompanying drawings, illustrating my invention, Figure 1 represents a perspective view of my improved grate-bar. Fig. 2 represents a central sectional view taken on line 2 2 in Fig. 1. 1 f

Referring to the drawings, the bar-frame 4. consists of two beams running parallel, and held together by the grate-bars 5, which are cast therewith.

The cross-bars 5 are each constructed with a curved central portion, 6, formed in the arc of a circle, and from each end of which curved portion extends the straight ends 7, which unite with the bar-frame 4. The curve 6 of the cross-bars lies in a plane normal to the plane of the entire grate.

Upon the outer sides of the bar-frame 4 are cast the lugs 8, which are designed as spacing-pieces for the compound grate-bars when they are mounted side by side across the bottom of the fire box to form the complete grate.

From the peculiar construction of the crossbars it is evident that when the cross-bars expand longitudinally the increased length will be mainly taken up by the curved portions, which will then be bowed more than when normal. By" virtue of the office of the curved cross-bars the bar-frame will be protected against breakage, and the cross-bars themselves will not be ruptured from theirjunctures with the bar-frame.

The cross-bars may be curved differently from what I have here shown and still be within the scope of my invention.

The compound grate-bar, as shown, repre sents a section of the grate entire; but it is to be observed that the entire grate may be constructed of the onecompound bar.

' I am aware that heretofore firegrates have been made in which the cross-bars are formed curved, or are formed with an angle bent in the bars which are inserted rigidly in the barframe. structions. My improvements differ from the old constructions, in that the cross-bars are formed with a curved central portion having straight ends extending therefrom, which ends are secured rigidly in the bar-frame, and I consider the features of the straight ends as an important advantage, because the same afford very efficient means for preventing the grate-bars from being ruptured or broken away from the bar-frame by the severe action of the expansion and contraction of the crossbars.

Having thus described my invention, Iclaim as new and desire to secure by Letters Patent 1. The combination, with a bar-frame, of cross bars formed with straight ends and curved portions intermediate of the ends, said ends secured to the bar-frame, substantially as herein described.

2. The combination, with a bar-frame, of cross-bars fixed in the bar-frame, and each constructed with a curved or bowed central portion having a straight portion at each end, substantially as herein described.

3. The combination, with a bar-frame, of

I therefore disclaim such con- I.

-the cross-bars 5, each formed with the curved Witnessesa integral cross-bars, each formed with a curved 5. The combination, with the bar-frame 4, central portion and straight ends, said ends of the integral cross-bars 5, each formed with 10 integral with the banframe, substantially as the curved portion 6 and the straight ends 7, herein described. substantially as herein described.

4. The combination, with a bar-frame, of THOMAS EVANS.

central portion, 6, and the straight ends 7, J. A. MILLER, J r., substantially as herein described. M. F. BLIGII. 

